It's claimed commuters using the Thameslink rail line which runs from Bedford to London may have to wait longer for improved services.
While changes have been made, including longer trains and the current redevelopment of Blackfriars and London Bridge stations, the National Audit Office is concerned progress is too slow.
More top news
Generally cloudy with some rain or heavy showers at times.
Rain easing for a time, but heavy showers possible later.
22 Albatross boats, glamorised by the likes of Brigit Bardot and Prince Rainier, are sailing in Norfolk and Suffolk this weekend.